title: Expression of metallothionein in ameloblastoma. A regulatory molecule?
abstract: BACKGROUND
  Ameloblastoma is a benign odontogenic tumor, exhibiting local invasiveness and high rate of recurrence. Metallothionein is a protein associated with tumorigenesis, serving as prognostic factor in different neoplasms. We are interested in mechanisms underlying ameloblastoma local invasiveness. Thus, we decided to analyze expression of metallothionein in this tumor.
  
  
  METHODS
  An immunohistochemical evaluation of metallothionein in ameloblastoma was carried out. As control, we assessed expression of the same molecule in calcifying cystic odontogenic tumor (CCOT), a non-invasive odontogenic neoplasm with ameloblastomatous epithelium.
  
  
  RESULTS
  We studied 12 cases of solid/multicystic ameloblastomas. Metallothionein was observed in all samples. This molecule was observed in columnar cells in the periphery and in central polyhedral cells. CCOT (four cases) also showed the presence of metallothionein. Morphometry of stained areas showed that expression of metallothionein in ameloblastoma was significantly higher compared to CCOT (P < 0.0001).
  
  
  CONCLUSIONS
  This protein may have an impact on ameloblastoma behavior. Metallothionein would act as a zinc reservoir for important proteases related to ameloblastoma biology, such as MMPs. This protein could also display pro-mitotic and anti-apoptotic features in the tumor.
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, University Center of Pará-CESUPA, Belém, Brazil. ribeiroalr@ig.com.br
authors.forename: André Luis Ribeiro
authors.initials: AL
authors.lastname: Ribeiro
authors.forename: Rafaela Moutinho
authors.initials: RM
authors.lastname: Nobre
authors.forename: Gabriela Cristina Marçal Avertano
authors.initials: GC
authors.lastname: Rocha
authors.forename: Isabella Haber
authors.initials: IH
authors.lastname: de Souza Lobato
authors.forename: Sérgio
authors.initials: S
authors.lastname: de Melo Alves Junior
authors.forename: Ruy Gastaldoni
authors.initials: RG
authors.lastname: Jaeger
authors.forename: João
authors.initials: J
authors.lastname: de Jesus Viana Pinheiro
mesh_terms: D000564:Ameloblastoma / Q000378:metabolism*; D016022:Case-Control Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008668:Metallothionein / Q000096:biosynthesis* / Q000235:genetics; D009361:Neoplasm Invasiveness; D009808:Odontogenic Tumors / Q000378:metabolism; D012878:Skin Neoplasms / Q000378:metabolism
chemical_list: D008668:Metallothionein